The invention relates to a creep-resistant and low-expansion iron-nickel alloy that has increased mechanical strength.
Increasingly, components are being produced from carbon fiber-reinforced composites (CFC), even those for products with security considerations, such as in aircraft manufacture. For producing such components, large-format linings are needed for tool molds, low-expansion iron-nickel alloys having about 36% nickel (Ni36) being fabricated to date.
Although the alloys used to date do have a thermal expansion coefficient that is less than 2.0×10−6/K, their mechanical properties are considered inadequate.
Known from U.S. Pat. No. 5,688,471 is a high strength alloy having an expansion coefficient of max. 4.9×10−6 m/m/° C. at 204° C. that comprises (in percent by weight) 40.5 to 48% Ni, 2 to 3.7% Nb, 0.75 to 2% Ti, max. 3.7% total content of Nb+Ta, 0 to 1% Al, 0 to 0.1% C, 0 to 1% Mn, 0 to 1% Si, 0 to 1% Cu, 0 to 1% Cr, 0 to 5% Co, 0 to 0.01% B, 0 to 2% W, 0 to 2% V, 0 to 0.01 total content of Mg+Ca+Ce, 0 to 0.5% Y and rare earths, 0 to 0.1% 5, 0 to 0.1% P, 0 to 0.1% N, and remainder iron and minor impurities. It should be possible to use the alloy for producing molds for composite materials that have low expansion coefficients, e.g. for carbon fiber composites or for producing electronic strips, curable lead frames, and masks for monitor tubes.
A high-strength low-expansion alloy with the following composition (in percent by weight) can be taken from JP-A 04180542: ≦0.2% C, ≦2.0% Si, ≦2.0% Mn, 35-50% Ni, 12% Cr, 0.2-1.0% Al, 0.5-2.0% Ti, 2.0-6.0% Nb, remainder iron. When necessary, the following additional elements can be provided:
≦0.02% B and/or ≦0.2% Zr. The alloy can be used inter alia for metal molds for precision glass sheet production.
In addition to a low thermal expansion coefficient, mold engineers involved in aircraft manufacture also desire an improved alloy that has greater mechanical strength compared to Ni36.